         (get-css-hour-minute-classes-for-time startTime)]
     ; Create new row if necessary
     (if (= rowNum (get-nr-rows-in-timetable-day day))
-        (add-new-row-to-timetable-day day))
+        (add-new-row-to-timetable-day! day))
 
     ; Update in-memory representation of timetable
     (timetable-add-lesson day

    (if (and moduleName modulesMapLessonSeq)
        (let [augLessonInfoSeq
              (doall (map (fn [modulesMapLesson]
                            (add-module-lesson moduleCode moduleName
                                                          lessonType
                                                          lessonLabel
                                                          modulesMapLesson
                                                          bgColorCssClass
                                                          isActuallySelected?))
                                    modulesMapLessonSeq))
              lessonInfoSeq (map #(dissoc %1 :divElem :moduleCode :lessonType
                                          :lessonGroup)
                                 augLessonInfoSeq)

   <td class='h23 m00'></td>
   <td class='h23 m30'></td>")

(defn- add-new-row-to-timetable-day!
  "Adds a new row to the 0-indexed day in the Timetable, where 0 = Monday,
   1 = Tuesday, until 4 = Friday."
  [day]
